OMAFRA field crop staff with the assistance from members of the Ontario Agri-Business Association (OABA) have completed the annual Provincial corn ear mould and mycotoxin survey. These mycotoxins, particularly vomitoxin (DON) produced primarily by Gibberella/Fusarium ear moulds can be disruptive when fed to livestock, especially hogs. The purpose of the annual survey is to assess grower and industry risk. Eighty-six percent of the samples tested low (<2.00 ppm) which bodes well for the 2017 Ontario corn crop.

From October 7th to 19th, a total of 179 corn ear samples were collected from across the province and rated for visible ear mould infection. Five consecutive ears were pulled from four random locations throughout a field. After recording pictures to document the presence of moulds, insect, bird feeding damage, etc, samples were placed into driers as soon as possible after collection. Dry ears were shelled and mixed through a sample splitter and delivered to SGS Agri-Food Laboratories in Guelph for vomitoxin (DON) analysis.

Results:

Of the 179 samples collected:

69% (124) had a DON concentration of less than 0.5 ppm;

17% (30) had a DON concentration between 0.5 and 2.0 ppm;

14% (25) had a DON concentration of 2.0 ppm or greater

While visual mould symptoms were apparent in some samples, they were much less pronounced than the 2016 survey, and more in line with what is observed most years. Vomitoxin analysis revealed DON concentrations lower than 2016, although incidences of elevated DON concentrations were still slightly higher than the long term average (Table 1). The vast majority of the samples (86%) tested below 2 ppm but as we state every year, growers need to be vigilant and assess each of the fields for the presence of disease, insect feeding, hybrid performance, etc. It is important to note that 5 of the 25 fields which had DON levels >2ppm were included in the survey because the growers had observed ear rots and were concerned. If these 5 fields are removed, the results would change slightly ( 71% (<0.5ppm), 17% (0.50 to <2.00 ppm) and 12% (≥2.00 ppm). A map showing the distribution of samples and their corresponding DON levels is presented in Figure 1.

Ear feeding by pests, particularly Western Bean Cutworm (WBC), and in a few cases, birds, presented an opportunity for greater mould infestation in some samples. In other samples with light WBC feeding, mould and vomitoxin appeared relatively low to non-existent, suggesting that while ear damage may predispose risk, increased mould or vomitoxin levels were not a certainty. Visual mould and elevated vomitoxin levels were also observed in samples with little or no feeding injury. WBC damage also seemed more apparent in areas which may not have traditionally received high WBC pressure, such as central Ontario. Growers in these areas may need to start monitoring WBC in the future.

Going Forwards:

This survey does not fully capture all regions of the province, and results can vary locally from field to field depending on hybrid, planting date, insect feeding or fungicide practices. These results may not fully capture what is occurring in your fields, and therefore monitoring is recommended. Timely harvest is important. Leaving diseased grain in the field allows the ear rot fungi to keep growing, which will increase the risk of mouldy grain and mycotoxin contamination.

If a field contains a significant level of ear mould, collect a representative sample prior to harvest and have it tested for mycotoxins before storing the grain or feeding it to livestock. If necessary segregate the harvested grain from your other corn. A lab test is often the only reliable way to definitively determine mycotoxin presence and levels.

When ear rots are present, the following harvest, storage and feeding precautions are advisable (Adapted from OMAFRA Pub 811, Agronomy Guide for Field Crops):

Harvest as early as possible especially susceptible hybrids.

If insect or bird damage is evident, harvest outside damaged rows separately. Keep and handle the grain from these rows separately.

Adjust harvest equipment to minimize damage to corn, and to remove smaller end kernels or those that have been damaged from mould or insect feeding. Clean corn thoroughly to remove pieces of cob, small kernels and red dog.

Clean bins before storing new grain and cool the grain after drying. If possible, segregate corn based on vomitoxin content to help match end use.

Exercise caution when handling or feeding mouldy corn to livestock, especially to hogs. Pink or reddish moulds are particularly harmful. Test suspect samples for toxins. Work with a nutritionist to manage vomitoxin levels in feed.

Preventing ear rots and mould can be difficult since weather conditions are critical to disease development, so a few things to consider for 2018. Hybrid selection is important but remember although some tolerant hybrids are available, none have complete resistance. Crop rotation can reduce the incidence of ear rots, while several foliar fungicides aimed at suppressing ear rots have also been registered. Cultural practices such as tillage have been shown to have limited success in preventing ear and kernel rots.

Acknowledgements:

We would like to thank the Grain Farmers of Ontario and SGS Agri-Food Laboratories in Guelph for their support of this survey and analysis as well as the Ontario Agri Business Association (OABA) and its members for their interest, support and participation. Sincere thanks to all of those who helped assist in the co-ordination and collection of samples: Agris Co-operative, Benjamins Agronomy Services, MacEwen Agricentre, Maizex Seeds, Parrish and Heimbecker, P.T. Sullivan Agro Inc., Sprucedale Agromart, TCO Agromart, as well as the several other corn producers and OMAFRA field crop staff who were involved.

Cool but dry conditions prevailed for the start of the corn growing season as May transitioned from a cooler than average April. May remained dry, with few precipitation events to delay planting. A few localized pockets in Southern Ontario were the exception, which received regular rainfall during the first half of the month. Planting started in earnest in many areas during the middle to end of the first week of May and progressed quickly once started. Planting conditions were generally good, although some growers on heavier textured soils reported that slow drying of subsoils were holding off early planting until ground conditions were more fit. Planting was nearing completion in many areas by the end of the following week (May 14), but continued on some heavier textured soils as well as those areas that had been receiving rainfall. Statistics Canada estimated that 2.0 million acres of grain corn and 0.250 million acres of silage corn were planted in Ontario in 2016.

While lingering cool soil temperatures slowed development of the earliest planted corn, emergence was generally good for most fields. With the lack of rainfall in May, corn that had been planted when parts of fields were not quite fit or had not been fully planted into moisture may have struggled to emerge or emerged late. While generally minor overall, this resulted in variability in some fields. Some growers on heavier soils reported emergence issues following the cool weather and rainfall of May 14-15th. A small amount of replanting was reported to have occurred.

The annual OMAFRA Pre-Sidedress-Nitrate-Test (PSNT) survey was conducted at the V3-V4 stage on June 6-7. With an overall average soil nitrate concentration of 11.2 ppm, levels were average to slightly higher than average. Given the lack of rainfall and low potential for soil saturation during May and June, nitrate losses from leaching or denitrification were unlikely. Below average precipitation in June maintained a wide window for weed control and sidedress nitrogen applications. With the exception of some moisture stress appearing on soils with poor water holding capacity in the drier parts of the province, the corn crop generally looked good and uniform through the end of June.

Pollination and Grain Fill

While some parts of the province received rain in July, many areas continued to be below normal, particularly the Bruce-Grey, Niagara and Central Ontario regions. Fields or parts of fields in these regions were beginning to show signs of moisture stress as corn leaves would wrap. There were some concerns as corn entered the moisture-sensitive tassel and pollination stages during the hot and dry conditions around the week of July 18. Some localized areas received thunderstorm related precipitation around this period.

During grain fill, there were reports of “tip-back” where several rows on the cob tips failed to pollinate and silks remained green. Warm temperatures continued to push crop development. As corn continued the grain filling process, significant rainfall events started to occur during August, with monthly precipitation totals ranging between 100-200% of normal for large portions of the province. Despite this, leaf diseases, where present, typically remained at low levels. Between timely planting and above average heat unit accumulation, there were few concerns about crop maturity as August came to a close.

Fall

Silage harvest started in earnest in many areas during the week of September 12, with the exception of some early harvesting of moisture stressed crops. September remained generally dry, which resulted in good silage harvest conditions. Some reported whole plant moisture being drier than what had been anticipated at the start of harvest. Yields were reported to be below average in areas with little rainfall and on soils with poor water holding capacity, while yields in other areas were reported to be average. Lab analysis results suggested vomitoxin levels in silage were higher than normal.

The annual OMAFRA grain corn vomitoxin survey was conducted from September 23 to 30. The survey indicated elevated vomitoxin levels with 26% of samples testing above 2 ppm. Long-term averages for this category run between 5 and 10%, suggesting some extra monitoring for grain management and feeding may have been required in 2016. Risks may have been elevated from the wet and humid conditions that persisted from August to early September. Poorer pollination of ear tips which resulted in silks remaining green and husk tips that tended to remain tight may have also contributed to this. Western bean cutworm feeding that opened husks for mould establishment was prevalent in many areas as well. The incidence of samples testing higher for vomitoxin decreased east of Toronto.

Harvest

As the growing season came to a close, heat unit accumulation ranged from average to 100-200 Crop Heat Units (CHU) higher than normal. Coupled with dry weather, corn harvest started early with some combining beginning as early as the last week of September. Harvest started in earnest around October 15, and progressed quickly as dry conditions prevailed for most of the province, resulting in a wide harvest window. Most growers reported moisture levels lower than what was typical for the time of year, and excellent test weights. With the exception of some localized pockets where soybean harvest was delayed, harvest was wrapping up in most areas by the end of the first week of November. Many growers reported yields that were above expectations considering the hot, dry growing season, with the exception of those on soils with poor water holding capacity, or regions which received well below average precipitation. As of December 14, Agricorp corn yields have been reported on 78% of insured acres with an average yield of 167 bu/ac. This compares well to the 10 year average yield of 167 bu/ac for those reported acres.

As another harvest season approaches, it also marks the time for deciding which corn hybrids to select for next year. It is always important to choose hybrids that are well adapted to the area and have good agronomic characteristics for your fields, although some characteristics commonly selected for in-grain production may not be as important for silage, such as standability.

Other corn silage hybrid selection criteria to consider are:

Yield

A traditional selection approach for corn silage hybrids was to plant a hybrid with high grain yield potential assuming grain yields were well related to whole plant yield. While this may have served as a general guide, hybrid trials in other jurisdictions suggest there is variability in grain stover ratios that may not necessarily make this true, and the highest grain yielding hybrid may not be the highest silage yielding hybrid.

Unlike grain corn, there are no public Ontario corn silage hybrid performance trials. Ideally look for performance data that has been replicated. Work with your seed supplier to select high-performing hybrids that have demonstrated consistency across a range of environments, such as soil type, precipitation and farm practices, as well as weather patterns over the years, if possible. This will increase the probability of selecting a hybrid that will better perform on your fields.

Quality

Research in the United States suggests with the exception of some hybrids with enhanced digestibility traits, variability in digestibility across standard corn silage hybrids tends to be fairly low, and digestibility is influenced more strongly by growing season or harvest management practices than hybrid selection. That being said, some gains could be achieved by selecting hybrids with above-average digestibility and avoiding those below average.

The University of Wisconsin quantifies corn silage quality through its MILK 2006 model. By combining forage analyses for crude protein, neutral detergent fibre (NDF), NDF digestibility, and starch and non-fibre carbohydrates, it provides an estimate of silage quality expressed as yield of milk per tonne of silage. In addition, by combining milk per tonne of silage with silage yield, the university produces an estimate of milk per acre, which provides an economic basis to compare silage hybrids. University trials showed the highest yielding hybrids may not always be the most economical hybrid if quality is lower than other high yielding hybrids.

Some traits, available in corn silage hybrids, are aimed at improving digestibility relative to standard dent hybrids. Historically, performance trials in other regions have suggested hybrids with some of these traits may be associated with lower or less consistent silage yields. This risk may be reduced with more modern, higher performing hybrids. When considering hybrids with improved digestibility traits, you should select carefully and ensure hybrids offer competitive yields compared with standard dent hybrids, and that they provide a good balance between feed quality and yield.

Maturity

When considering silage hybrid maturity, a good practice for maximizing yield potential is to select a hybrid that has a slightly longer season, such as 100 to 200 crop heat units longer, than grain corn normally grown in the area. In general, corn plants may reach proper harvest moisture content for packing and fermentation around two weeks before physiological maturity. Selecting a slightly later maturing hybrid can help maximize the growing season. It is a good idea to work with your seed supplier to select a silage hybrid with a maturity rating that would accomplish this.

Similar to grain corn production, varying silage hybrid maturity can help spread weather risk and harvest workload if harvesting silage at the proper moisture content for good packing and fermentation is an issue. Moisture variability may be less beneficial if you harvest silage in a narrow window, such as when using custom silage harvester.

Flexibility

Planting a portion of expected silage acres to a hybrid that could be used for either grain or silage production, sometimes referred to as dual-purpose hybrids, could provide flexibility for yield variability. It is a good idea to select a high-yielding grain hybrid with high digestibility and maturity suited for grain production. In lower yielding years, this hybrid could be used to supplement silage volume, while in higher yielding years it could be combined for grain.

The OMAFRA Field Crops team conducted its annual vomitoxin survey to assess the presence of corn ear mould and grain vomitoxin in the 2016 corn crop. Vomitoxins can be produced by Gibberella and Fusarium ear moulds and can be disruptive when fed to livestock, particularly hogs.

A total of 121 samples were collected from Southern to Eastern Ontario from September 23rd to 30th. In most cases, five consecutive ears were pulled from four random locations throughout a field. After recording pictures and rating ears for the presence of moulds and insect or bird feeding, samples were placed into driers as soon as possible after collection. Dry ears were shelled and mixed through a sample splitter, and delivered to SGS Agrifood Laboratories in Guelph for vomitoxin (DON) analysis.

Results:

Of the 121 samples collected:

48% (58) had a DON concentration of less than 0.5 ppm;

26% (31) had a DON concentration between 0.5 and 2.0 ppm;

26% (32) had a DON concentration of 2.0 ppm or greater

Visual mould symptoms were much more prevalent in the 2016 survey than what has been observed in recent years. Similarly, vomitoxin analysis revealed DON concentrations that were higher than surveys from the past couple of harvest seasons, with the most recent year of comparable results being 2011 (Table 1). These results suggest extra vigilance in monitoring and managing DON concentrations in corn may be required in 2016. While some samples with elevated levels of DON were present across most regions sampled, in general there appeared to be a greater incidence of elevated DON levels for samples collected from Southwestern Ontario (Figure 1).

Feeding Damage

Feeding on ears by pests, particularly Western Bean Cutworm (WBC), incomplete pollination, and open ears present an opportunity for greater mould infestation. While visual mould symptoms were generally more severe where ear feeding from WBC was present, mould symptoms and elevated vomitoxin levels were also observed on some ears and samples with little or no feeding injury. While WBC feeding may predispose risk, monitoring will be important in a higher risk year such as 2016 whether or not WBC feeding was present.

Going Forwards:

This survey does not fully capture all regions of the province, and results can vary locally from field to field depending on hybrid, planting date, insect feeding or fungicide practices. These results may not fully capture what is occurring in your fields, and therefore monitoring is recommended. If you suspect grain vomitoxins may be present, it is recommended to sample ears in a similar fashion as described above, hand shell, mix, and submit a grain sample as soon as possible after collection to one of the several labs in the province that test for vomitoxin.

When ear rot is present, the following harvest, storage and feeding precautions are advisable (Adapted from OMAFRA Pub 811, Agronomy Guide for Field Crops):

Harvest as early as possible especially susceptible hybrids.

If insect or bird damage is evident, harvest outside damaged rows separately. Keep and handle the grain from these rows separately.

Adjust harvest equipment to minimize damage to corn, and to remove smaller end kernels or those that have been damaged from mould or insect feeding. Clean corn thoroughly to remove pieces of cob, small kernels and red dog.

Clean bins before storing new grain and cool the grain after drying. If possible, segregate corn based on vomitoxin content to help match end use.

Exercise caution when handling or feeding mouldy corn to livestock, especially to hogs. Pink or reddish moulds are particularly harmful. Test suspect samples for toxins. Work with a nutritionist to manage vomitoxin levels in feed.

Acknowledgements:

Appreciation is extended to the Grain Farmers of Ontario and SGS Agrifood Laboratories in Guelph for their support of this survey, and to the OMAFRA field crops team, industry participants and growers that assisted in the co-ordination and collection of samples.

Co-Authored with Ian McDonald, OMAFRA and Ken Janovicek, University of Guelph

OMAFRA Field Crop Unit staff have traditionally conducted a Pre Sidedress Nitrogen Test (PSNT) survey across Ontario at the beginning of June each year to examine the natural soil nitrate available. In the past, 80-100 samples would be collected from fields across the province that had not received any preplant nitrogen other than up to 30 lbs of N banded at planting.

In 2016, we are transitioning to reporting the results of the GFO supported Soil Nitrogen Sentinel project (http://bit.ly/1WMzSb4). The goal of the project is to collect samples over time from several permanent sentinel locations to better understand how natural soil nitrate levels change over the spring. Soil organic N mineralizes over time in the spring at different rates due to temperature, moisture, soil texture, crop rotation among other factors.

Soil samples were collected from 23 locations beginning at planting time (~May 1), through the V1-V2, V3-V4, crop stages with additional sampling events planned for the V6 and V9 stages where “V” designates visible collars on the corn plant. The V3-V4 sample timing coincides with the historical annual PSNT survey, and together with data from an additional 12 supplementary sites is included in this years survey. Ongoing results for the Nitrogen Sentinel project are available at http://bit.ly/1rd6z3F.

In general, the spring of 2016 has been cooler and drier than average through April and May, although accumulated CHU’s have caught up to above normal as of the last week of May. While cooler and drier conditions may reduce nitrogen mineralization from organic sources (supply) in the soil, the drier conditions reduce the potential for loss through leaching or denitrification.

A total of 35 samples were collected from June 6 to June 7 in corn generally in the V3-V4 stage from locations scattered throughout Southern Ontario, as well as a few in central and eastern Ontario. With an overall average of 11.2 ppm in 2016, soil nitrate levels tended to be average or slightly above average relative to the 5 previous survey years (2011-2015), while slightly lower than 2015 values which were well above normal (Figure 1).

Figure 1. PSNT survey results by soil texture for years 2011-2016.

PSNT values were similar on fine and medium textured soils (Table 1), but lower on coarse textured soils, which is generally consistent with N credits and past PSNT surveys. When summarized by previous crop, soil nitrate values were similar for corn following cereals (predominantly wheat) or soybeans, but lower when following corn, again consistent with N credits (Table 2).

Table 1. Soil nitrate by soil texture

Soil Texture

Soil Nitrate (ppm)

Coarse

8.3

Fine

11.8

Medium

12.0

Table 2. Soil nitrate by previous crop

Previous Crop

Soil Nitrate (ppm)

Corn

6.7

Soybeans

11.4

Cereals

11.8

Recommendations:

In general, soil nitrate values are similar to average, suggesting normal nitrogen practices should be adequate for these sites this year. However, these values are a relative indication only, and should not be used as a recommendation for nitrogen rates on any given farm. Soil nitrate values are highly influenced by the environment (agronomic practices, local weather). For instance, if you are in an area which has received significantly more rainfall than other parts of the province, you may have also experienced more loss than is reflected in these results. The only way to know soil nitrate concentrations on your own farm is to pull soil nitrates from your own fields.

To collect PSNT samples, collect several 12″ soil samples across a field using a soil probe. Sample parts of fields differently if there is reason to suspect differences in N content (past history, soil type, topography etc.). Take a well-mixed representative sub sample of approximately 1 lb to fill a lab box or bag. Samples should be chilled to prevent further mineralization and sent to a lab as soon as possible. PSNT recommendations for a given soil nitrate test are only valid for natural soil nitrate supply, not valid where any nitrogen fertilizer would be collected in the sample (preplant, broadcast N). A modest amount of N applied with starter (ie. 30 lb/ac) is OK provided sampling can be taken mid-row to avoid these bands.

OMAFRA has recently revised PSNT recommendations to include both a soil nitrate measurement and an expected yield that can be achieved (Table 3).

Table 3. Revised PSNT Recommendations

Soil

Expected Yield (bu/ac)

Nitrate

120

143

167

191

215

239

(PPM)

Sidedress Nitrogen Fertilizer Recommendations (lb N/ac)

0

176

197

218

240

261

282

2.5

163

184

205

225

246

267

5

151

171

191

211

231

252

7.5

138

158

177

197

216

236

10

126

144

163

182

201

221

12.5

113

131

149

168

187

206

15

99

117

135

153

172

190

17.5

83

102

120

138

156

175

20

57

86

105

123

141

159

22.5

0

60

88

107

126

144

25

0

0

63

90

110

128

27.5

0

0

0

66

92

111

30

0

0

0

0

68

93

32.5

0

0

0

0

0

69

35

0

0

0

0

0

0

Thanks to our N-Sentinel trial co-operators, as well as Greg Stewart, Maizex Seeds for providing supplementary nitrate samples for the 2016 PSNT Survey.

Past research in Ontario and abroad has demonstrated the importance of uniform emergence for maximizing corn yield. At the Southwest Ag Conference in January, Randy Dowdy, 2014 National Corn Growers Association yield contest winner from Georgia proposed the “flag test” – returning to a plot every 12 or 24 hours and flagging every newly emerged plant using a different coloured flag for each visit as a simple means of assessing emergence variability on your farm. Comparing flag tests for different practices within the same field (cover crops, tillage) may also demonstrate how practices influence variability. Several growers and industry personnel have been conducting their own flag tests in 2016.

If you have not conducted a flag test, but are interested in evaluating plant variability in your field, it is not too late. Dr. Dave Hooker at the University of Guelph, Ridgetown Campus has developed a protocol to measure variability during leaf stages. The protocol provides measurement guidelines to make data collection across locations as consistent as possible and is outlined below. A spreadsheet for recording data is available here: PPV Study – Data Recording.

PROTOCOL:

Plant-plant Variability Study in 2016

Recent studies have indicated that plant-to-plant variability (PPV) in crop development reduces grain yield. We are now into June; it is obviously too late to formally organize experimental designs for each field (perhaps in 2017). It is not too late, however, to organize a protocol for collecting data from multiple field locations that have been setup for studying PPV.

Objective: to further quantify the impact of PPV on grain corn yield as affected by various agronomic practices.

Protocol: growers and researchers are invited to participate in the study by recording data on a per-plant basis from within row segments of various agronomic practices in the same field. In 2016, we understand that every PPV study will consist of different treatments and a range of row segments and replications. However, a standardized measurement protocol and data collection would facilitate data analysis and strengthen conclusions.

If you are interested in participating in this study:

Please contact Dave Hooker (dhooker@uoguelph.ca).

Download the spreadsheet for data entry. Tailor the data entry sheet based on your field study. An example field study is provided in the spreadsheet. Dave Hooker will provide assistance. Briefly, every plant in all row segments of the study will be tagged with a unique code. This code will be based on the replication number, treatment number (e.g., cover crop tmts, tillage system tmts, seed tmts, etc.), planter row number, and the plant number in the row segment).

It is obviously too late to record corn emergence timing data; however, it is not too late to setup a study to observe developmental differences and PPV (start with leaf number measurements instead of emergence timings).

The full measurement protocol is as follows (see also the spreadsheet for further clarification):

Be sure to setup the data entry sheet correctly (see point 2 above).

Measure the length of each row segment (column “I” in the data worksheet).

Estimate the distance between plants (within an inch) and record in column J in the data worksheet. The first number (see 15 cm in the “data example” worksheet) is the estimated distance from plant 1 and 2 in the row segment). These estimates do not have to be precise – just eyeball the plant spacing.

Label the plants. This is critical for good data. Each plant needs to be tagged with a plant code (see spreadsheet “data example” for explanation of codes). Tags are available – write or print the code on the tag, and tag the plants when recording leaf numbers (at approx. 8-11 leaf tips). Be sure to place the tag high on the plant to avoid soil splash.

Record emergence date for each plant (if data are available).

Count leaf tips for each plant when most plants have between 8-11 leaf tips visible.

Record the day of silking. Silking occurs when the first silk appears.

Optional. Record the day of pollen release. This occurs when the first pollen is released.

Ear harvest. Harvest the ear (or ears) and place in a mesh bag along with the tag with the plant code. If there are 450 tagged plants in the study, you should have 450 mesh bags. Mesh bags from plants barren of ears will only have the tag. The bags and ears should be dried ASAP until constant weight, then each ear shelled and weighed. The weigh scale should read to the gram. Record the weight in the spreadsheet.

The corn nitrogen calculator app generates a recommendation for the most economical N rate for a corn field. It is based on more than 40 years of Ontario research and takes into account soil type, rotation, and the cost scenario (i.e. anticipated cost of N and price of corn). The app allows you to save the recommendations for each field and to generate an email report.

Aftermarket planter modifications to control row unit down pressure have been well promoted into the Ontario marketplace, and are advertised for their ability to improve planter function, and final yields. The basic principles behind the modifications have merit, but the relative yield impacts of the different modifications, and their ability to respond above and beyond what is currently available in the marketplace is unknown, and has generally not been well investigated beyond anecdotal evidence. As a result, it is difficult to predict the returns these modifications would provide, making it difficult to make recommendations of when or where the use of these modifications may be most warranted.

Methods:
Three trials were conducted in Ontario in 2012, and were located at Maryhill, Ancaster, and Highgate. All three locations were conventionally tilled and planted with a 6-row John Deere 7200 Conservation planter equipped with Precision Planting 20/20 AirForce down pressure control system equipped with both down-pressure and up-pressure control airbags. Soil test P and K tested ranged from medium (MR) to rare (RR) probabilities of profitable responses. A total of seven treatments were conducted at each site, and included three auto down pressure settings and four manual down pressure settings (Table 1). Trials were conducted as a randomized complete block design, with three to four reps at each location, all within existing corn fields to negate potential ‘edge’ effects. Fields ranged from flat (Highgate) to undulating topography (Ancaster). All yield data was collected as whole plot weights by combine and weigh wagon.

Results:
Significant differences in yield were only observed at the Maryhill and Ancaster sites (Table 1). At Maryhill, the “Auto Medium” setting was significantly lower than the “Auto Heavy” and “Manual 125 lb” settings, which were the highest yielding treatments. At Ancaster, “Manual 0 lb” and “Manual 375 lb” were significantly lower yielding than the “Auto Light”, “Auto Medium” and “Manual 125 lb” settings. No significant differences in yield were observed at the Highgate location. At locations where yields between some treatments were significantly different, the only treatments which were consistently significantly different was the “Manual 125 lb” setting which was among the highest yielding at both the Maryhill and Ancaster sites.

† Means comparisons are valid within site only, means followed by
the same letter are not significantly different at the 5% level

Summary:

Overall, down pressure treatments did not appear to have a significant impact on yields in 2012, but it was interesting to note that no (0 lb) down pressure and very high (375 lb) down pressure at the Ancaster site did result in significantly lower yields. Given the dry weather during the spring, soil conditions at planting time were generally very good at all sites regardless of variation in topography etc., thus it may be difficult to generalize the conclusions based on these sites and this single growing season.

Next Steps:

This was the first year of a two year project. It will be conducted in a similar manner in 2013, with a greater emphasis on attempting to plant under variable soil moisture conditions where this technology may be most warranted.

Acknowledgements:

Appreciation is expressed to Innovative Farmers Association of Ontario, Grain Famers of Ontario and Pioneer Hi-Bred for support of this project. In addition funding was supplied by the CAAP program administered by AAC. We are grateful to Precision Planting and to Clifford Precision for their support on the equipment side of the project. Thanks also to the farm co-operators and technical expertise provided by K. Janovicek of the University of Guelph.